1) You sure can define a range with units! The error message tells you exactly whats wrong and how you can correct it:
But even if you supply the second value (and its a good habit to apply the unit to 0, too) your calculation would not work because you should not use a range for this task. You get the error that you can't compare a range to a scalar:
You should use a vector instead of a range. You could use Terrys utility function to create that vector or use a dirty, undocumented trick to turn a range into a function - you simply type an equal sign after the 100m to evaluate the range and bingo, its turned into a vector. The calculation still would not work as you can't compare a vector (x) to a scalar (L.2), too. So its a good idea to turn your calculation into a function and call that function vectorized:
You should provide an otherwise statement as what you had typed missed the cases x<=0 and x=L.2.
